e was ''a so-called Pink,'' Kinbote says of a campus colleague, 'who believed in what so-called Pinks believe in (Progressive Education, the Integrity of anyone spying for Russia, Fallouts occasioned solely by U.S.-made bombs, the existence in the near past of a McCarthy Era, Soviet achievements including 'Dr. Zhivago' and so forth).'' Although ''Pale Fire'' is part satire, that bravura passage has Nabokov speaking very much in his own voice; little did he guess that, 40 years later, the McCarthy era would still haunt America.

From Richard Rovere's admirable 1959 ''Senator Joe McCarthy'' onward, very many books about the era and its protagonist have appeared. In the latest, the long, detailed, interesting but puzzling ''Reds,'' Ted Morgan, a biographer of Franklin D. Roosevelt, Winston Churchill and Somerset Maugham, covers the ground with some fresh material and, as he hopes, with a new angle. The result is really more than one book, and they don't quite hang together: McCarthy enters (stage right) only after more than 320 pages, or well over halfway through, and no more than 4 out of 15 chapters are devoted to him.

His story remains fascinating, and hair-raising. Born in Wisconsin, Joe McCarthy displayed application and ability at school and college. He also displayed from a young age a tendency to embroider the record. As Morgan says, McCarthy learned early that ''he could lie and get away with it.'' In 1939, partly by means of mendacious attacks on his opponent, he became the youngest circuit judge ever elected in Wisconsin. Soon he was propelled into national politics, by way of war service in the Pacific and by way of more fabulizing. McCarthy allowed the people of Wisconsin to believe that he had been wounded in action (or, still more inventively, ''while helping to remove a pregnant woman from off a submarine''), when actually he had injured himself in a prank during the traditional festivities crossing the Equator.

He was an obscure figure when he reached Washington in December 1946, and not much better known in 1950 when he jumped on the anti-Communist bandwagon with his explosive ''I have in my hand'' speech at Wheeling, W.Va., claiming that the State Department was a nest of Communists. Thus began the McCarthy era, although Morgan rightly stresses that anti-Communist purges and Communist espionage both predated McCarthy's own demagogic career.

However often told, the story never palls: the increasingly wild charges, the atmosphere of suspicion and dread, the attack on Gen. George C. Marshall and then the whole United States Army, the televised hearings, the breaking of a malign spell over American political life with Joseph Welch's superbly theatrical riposte -- ''Little did I dream you could be so reckless and so cruel. . . . Have you no sense of decency, sir, at long last?'' -- and McCarthy's censure by the Senate in 1954. Less than three years later he was dead.

Along with his bullying and braggadocio, there was a huge self-destructive streak in McCarthy's makeup. It showed in the easily demonstrable lies he told, it showed in the drinking that polished him off at only 48, it showed in his patronage of the odious if preposterous Roy Cohn and his boyfriend David Schine, whose cavorting around Europe made a laughingstock of America and much aided the Communist cause. But then so did the whole McCarthy era.

Those who come out of this story worst aren't so much McCarthy and his acolytes as the politicians who recognized him for what he was but lacked the courage to stand up to him. ''Joe's just a loudmouthed drunk,'' Lyndon Johnson told Bobby Baker. Other senators knew that, and in his last years they got up and left the dining room when he entered. But that was only after his star had fallen. Until then, Democrats as well as Republicans had lined up behind him, or at least refused to call his bluff.

But telling the immediate story of the McCarthy era is only one part of this book. Its subtitle is ''McCarthyism in Twentieth-Century America,'' and it can't quite make up its mind what its theme is supposed to be. Morgan begins with what he thinks is the provocative claim that ''the cold war began in 1917,'' but this is a truism. A. J. P. Taylor's history of European international relations from 1848 to 1918, written 50 years ago, ended with the words that ''Europe was superseded'' after World War I by the ''competition between Communism and liberal democracy.''

In Morgan's account, the conflict had taken shape with American involvement in the Russian Revolution, and the abortive military intervention against the Bolsheviks. Following that episode, he plunges headfirst into the murky world of espionage. From the arrival of the first Soviet trade mission in 1924, the Russians established a large spy network in America, in some ways connected with the official and open Communist Party, but also with the larger sway that Communism held over cultural and intellectual life in the 1930's and 40's.

The evidence of Venona, the transcripts of the Soviet secret signal traffic intercepted and decrypted by American intelligence, is conclusive about the extent of that operation: with a strange irony, one could say that McCarthy didn't know the half of it. All the same, to write, as Morgan does, that if only Venona had been released at the time, ''the swing of the pendulum to hysterical anti-Communism could perhaps have been avoided,'' is idle; of course the transcripts could not have been made public then.

Morgan devotes the last part of his book to a feverish gallop through events since McCarthy: the F.B.I.'s ever more frantic pursuit of an ever tinier Communist Party, the sex lives of John F. Kennedy and Martin Luther King Jr., the birth of the New Left, Vietnam, Watergate, Iran-contra, whatever. All this is designed somehow or other to illustrate the thesis that ''just as McCarthyism began long before McCarthy, it endured long after him.''

Does this mean anything? ''McCarthyism'' could have a truly useful definition: the calculated and unprincipled use of mendacious allegations for political purposes. But if it comes to be used (as it too often is) to mean any charge uncomfortably near the bone, or if alternatively it covers any kind of demagoguery, falsehood and trickery, then the very concept is rendered empty and meaningless.

As to Morgan's peroration -- or concluding rant -- about George W. Bush, 9/11, African uranium and the ''pattern of deceit'' behind the White House's case for war with Iraq, one can (as it happens) share the author's inclination on these subjects while wondering whether ''McCarthyite methods'' is in any sense a helpful way of describing the debate over the current war. It did not require McCarthy, after all, to teach politicians the uses of misrepresentation.

All of which leaves ''Reds'' looking curiouser and curiouser. Despite being quite unillusioned about Communism, Morgan misses the point. McCarthy did huge damage to American life, but a large part of the damage was done to the honorable anti-Communist cause -- and to honesty on the left. Nearly 50 years ago, when the senator was still at large, the journalist Dwight Macdonald pointed out that ''the liberals have never honestly confronted their illusions in the 30's and 40's about Communism but have instead merely counterposed a disingenuous defense, a blanket denial to McCarthy's equally sweeping attack.''

Before the McCarthy era began, and then after it ended, two politically very different Englishmen said what needed to be said. George Orwell almost certainly never heard of Joe McCarthy: the Wheeling speech came a matter of weeks after his death. But not long before he died, Orwell had specifically warned the Americans about the danger of fighting Communism with the kinds of methods Communists themselves used.

Then in 1960, William F. Buckley Jr. tried to persuade Evelyn Waugh to contribute to National Review, and sent him ''McCarthy and His Enemies,'' the apologia he had written with L. Brent Bozell. But Buckley got an elegant flea in his ear. Most Englishmen regarded McCarthy as a regrettable figure, Waugh replied, and the book ''will not go far to clear his reputation.'' Plainly there had been need for an investigation into Soviet espionage, but it was just as clear that McCarthy was not a suitable man to undertake it, Waugh said, and those who sympathized with the anti-Communist cause ''must deplore his championship of it.'' Despite all the bitterness of the McCarthy era and its residue, that remains something like the last word.